Circuit-closer for door-alarms.



' m sty/.220.

PATENTED SEPT. 24, 1907.

L. E. L. THEMKE.

CIRCUIT CLOSER FOR DOOR ALARMS.

APPLICATION FILED IAB. 14, 1907.

Inventor,

Witnesses:

Attorneys LOUIS E. L. THEMKE, OF STRATHOONA, ALBERTA, CANADA.

CIRCUIT-CLOSER FOR DOOR-ALARMS.

Specification of Letters Patent.

Patented Sept. 24, 1907.

Application filed March 14, 1907. Serial No. 362,409.

To all whom it may concern:

Be it known that I, Lo UIS ERNEST LEoroLD THEMKE, residing at.Strathcona, county of Strathcona, in the Province of Alberta, Canada,machinist, have invented certain new and useful Improvements inCircuit-Closers for Door-Alarms; and I do hereby declare that thefollowing is a full, clear, and exact description of the invention, suchas will enable others skilled in the art to which it appertains to makeand use the same.

My invention relates to door alarms; the object of my invention is toprovide a construction adapted to cooperate with the door lockconstruction disclosed in my pending application for patent Number327,114, to close the circuit when the door lock is tampered with fromthe outside; and, my invention consists of the construction, combinationand arrangement of parts, as herein illustrated, described and claimed.

In the accompanying drawings, forming part of this application, I haveillustrated one form of embodiment of my invention, in which drawingssimilar reierence characters designate corresponding parts, and inwhich:

Figure 1 is a transverse section through a portion of the door and itslock, illustrating the knob stem in longitudinal vertical section; and,Fig. 2 is an edge elevation of a portion of the door, showing thearrangement of the battery.

Referring to the drawings, A designates a door having an opening a inits front edge adapted to receive the locking mechanism B. Disposed trztnsversely through the door A is a tubular knob stem 1), supported onthe inside of the door by the knob rose b, all of which construction maybe of any ordinary construction, but is preferably similar to thatdisclosed in my pending application, Number 327,314, for an improvementin locks.

Disposed on the inside face of the door is a knob rose 1 oi insulatingmaterial. Carried by the inner face of the knob rose 1 is a contact ring2, adjacent which is disposed a contact member 3 pivoted to a bracket 4.secured by means of the screw 5 to the knob stem 1). The contact member3 is provided with a head 6 adapted to work into slot 7 formed in thewall of the knob stem 1). A spring 8 is carried by the bracket 4, and isadapted to normally maintain the head 6 projected into the bore of theknob stem, while the opposite end oi the pivoted contact 3 is adapted tocontact with the ring 2 when the head 6 is within the bore of the knobstem. A conductor 9 is carried to a contact plate 10, which is securedto the knob rose 1 and placed in electrical connection with the contactring 2, as by means of the pin 11. The other wire 12 of the circuit hasits lower end secured to the outside plate of the locking mechanism B,and the upper ends of the wires 9 and 12 are connected with a battery13, which is disposed in the recess 14 in the door A. A suitable plate15 is adapted to maintain the battery 13 in position. A removable pin 16is disposed in the outer end of the knob stem 13, and is adapted tomaintain the contact member 3 in depressed position against the tensionof the spring 8, so that the circuit is normally open.

In the operation of the alarm, anyone tampering with the outside of thelock and removing the pin 16, the headed end (3 of the pivoted contact 3will be thrown upward into the slot 7, and the opposite end of themember 3 thrown into Contact with the ring 2-, under the tension of thespring 8, thereby closing the circuit.

The contact member 3 being carried by the knob stem Z), the stem may berotated freely without displacing any ot' the parts. The circuit betweenthe lower end of the wire 12 and the contact member 3 is completedthrough the locking mechanism 15.

Any suitable form oi alarm may be included in the circuit comprised bythe wires t) and 12, the locking mechanism 13 and the battery 13.

Having thus tully described my invention, what I claim as new, anddesire to secure by Letters Patent, is:

1. In combination with a door having a tubular knob stein disposedtherethrough, a circuit closing mechanism comprising a battery carriedby the door, an electrical circuit leading from the battery, removablemeans carried by the knob stem and arranged to normally maintain thecircuit open, and means for closing the circuit when the removahle meansis removed.

2. In combination with a door, a knob rose of insulated material, acontact ring carried by the knob rose, a tubular knob stem disposedthrough the knob rose, a pivoted con tact member '1. 'ried by the knobstem, an insertible member disposed in the knob stem and adapted todepress the pivoted contact, and an electrical circuit between the ringand the pivoted member adapted to be closed when the insertiblc memberis removed from the knob stem.

2'3. In combination with a door having a plurality of re cesscs therein.a battery disposed in one recess, a plate disposed over the recess andadapted to secure the battery in position. a tubular knob stem disposedthrough the door, a pivoted contact member carried by the knob stem, acon tact ring disposed around the tubular knob stem, an electric circuitincluding the battery. the contact ring and the pivoted member, andmeans for maintaining the pivoted member in one position to open thecircuit.

I. In combination with a door a tubular knob stem disposed through thedoor and provided with a slot, a knob rose of insulating materialcarried by the door and adapted to support the knob stem. a pivotedcontact member carried by the knob stem and adapted to project into theslot therein. a spring adapted to maintain the pivoted contact member insaid slot, means for forcing the pivoted member away from the knob stem,at contact ring carried by the insulated knob rose, and an electriccircuit including the contact: ring and the pivoted contact member.

In witness whereof I have hereunto set my hand in the presence of twowitnesses.

LOUIS E. L. 'IHEMKE.

Witnesses FRANZ Scrrnrnan, Bnn'rrra B. JoNns.

